Apparatus for discharging an ash hopper



Jan. 16, 1934. F. a. ALLEN APPARATUS FOR DISCHARGING AN ASH HOPPER FiledSept. 15, 1930 4 Sheets-Sheet l Jan. 16, 1934. F. B. ALLEN 1,943,780

I APPARATUS FOR DISCHARGING AN ASH HOPPER Filed Sept. 15. 1930 4 sheetssheet 2 Jmnntoc FHA/VA AlZf/ if was Jan. 16, 1934. F. B. ALLEN APPARATUSFOR DISCHARGING AN ASH HOPPER Filed Sept. 15. 1930 4 Sheets-Sheet 3 M nM FE'AN/(B AME/V 4 M Jan. 16, 1934. F. B. ALLEN APPARATUS FORDISGHARGING AN ASH HOPPER 4 Sheets-Shet 4 Filed Sept. 15, 1950 PatentedJan. 16, 1934 APPARATUS FOR DISCHARGING AN ASH HOPPER Frank B. Allen,Lower Merion Township, Mont-' gomery County, Pa., assignor to The Allen-Sherman-Hofi Company, a corporation of Pennsylvania ApplicationSeptember 15, 1930 Serial No. 481,938

9 Claims. (01. 3ll2- 52) This invention relates to dust disposal systemsand more particularly to new and improved methods of and apparatus forremoving fine ash from the bottom of a collecting hopper of a powerplant furnace.

The handling of finely divided solids, such as' .dust particles, anddischarging such material from hopper or collecting chambers has longbeen a troublesome problem without an adequate solution, so far as I amaware. The dust is ordinarily carried by gases and collected in a gascontaining chamber in which the gas pressure is usually somewhat belowatmospheric pressure. Oftenit is dangerous to permit air to mingle withthe gases while discharging the dust material from the collectingchambers. An

illustration is found where blast furnace dust is to be removed fromdust catchers while blast furnace gas is present.

In another field, namely; in steam power plant furnaces and the likewhich are adapted to burn ash creating fuel and particularly those whichare designed for burning powdered coal, a considerable quantity of dustor fine ash is carried from the combustion chamber of the furnace towardthe stack by the outflowing gases. This dust usually settles out of thegases before they are discharged into the stack proper and is' collectedin dust hoppers. In the continuous operation of the furnace thesehoppers must be periodically emptied of such dust and ordinarily bottomdischarge openings are provided. It will be understood that induceddraft fans create a partial vacuum in the furnace and suck gases out ofthe furnace and deliver the gases into the stack. If these dust hopperopenings are closed by an ordinary type of, gate or closure, air isallowed to enter the hopper and to pass up into the furnace and to thestack whenever these bottom discharge gates are open. This isundesirable as the admission of air into the dusthoppers may seriouslyafiect the gas balance which is sought to be maintained in the furnaceand lower the efficiency of the furnace, and furthermore carry abrasivematerial into the induced draft fans in the furnace. Elaborate valveshave been proposed to keep the dust out of the fans when the hoppers areopened. Often the dust is carried out of the stack and deposited onadjacent property. thereby constituting a nuisance. It is among theobjects of my invention, therefore, to provide a means and method ofremoving dust from a hopper by a suction induced draft of air or gaswithout creating any undesirable conditions inside or outside of thehopper or con tainer while so doing.

Another object of my invention is to provide a 'method of removing thecontents of adust hopper without disturbing the gas balance in a furnacein communication with the'hopper.

Another object of my invention is to provide an automatic means andmethod of discharging the content's'of a dust hopper without causing aback flow of dust in the hopper or to .indu'ced draft fans or otherapparatus in communication therewith.

According to myinvention the dust is drawn out of the hopper orcontainer by suction which,

instead of decreasing or destroying the partial vacuum therein, mayactually increase it, thereby favorably effecting the gas balance andeffectivelypreventing dust being carried back into the system from thehopper. Moreover. my

method and apparatus are automatic in operation while the dust dischargedevices or valves are open, andrequire no attention. The absence ofmoving parts in the .apparatus that aresubject to wear makes for longlife of the device.

Further objects will be apparent from 'the following detaileddescription wherein similar characters of reference designatecorresponding parts and wherein:

Fig. 1 is a view partly in section illustrating a dust handling systemembodyingmy invention and applied to three dust hoppers of a fuel burn-'ing furnace; o

,Figure 2 is a sectional view of an ejector adapted. to create a suctionin the discharge conduits; v I Fig. 3 is a vertical longitudinalsectional view of. the hopper discharge device of Fig. 1;

Fig. 4 is a sectional view taken on line-,4-4 of Fig. 3;

Fig. 5 is a perspective sectional view of a modified form of dischargedevice;

Fig. 6 .is a view similar to Fig. 1 but illustrating a systemincludingthe modified form of discharge valve shown in-Fig. 5 p

Fig. 7 is diagrammatic view of a discharge system'embodying a pluralityof electors disposed in the discharge conduit;

Fig. 8 is a modification of part of' the apparatus of Fig. 1 showing theuse of gas from the dust container for removing the dust.

In Figs. 1, 3 and 4 of the drawings the structo as by the bolts 2.is acasing 3 provided with oppositely aligned substantially horizontalportions 4 and 5 which serve as hearing housings for a rotary shaftwhich functions as a valve.

The horizontal portions 4 and 5 are bored longitudinally as at 6 and 7respectively and are adapted to receive the bearing sleeves 8 and 9. Arotary valve 10 is positioned with its ends in sleeves 8 and 9. Thecenter portion of member 10 is of a somewhat reduced diameter to allowthe free passage of fine material from the hopper into the lower part ofthe valve chamber or casing 3. The inlet end 11 of the valve 10 is boredcentrally to provide a tapering aperture 12 having a port 13 at itsinnerend adapted to co-operate with the port 14 in the wall of portion 4for effecting communication between the atmosphere and the interior ofthe valve chamber 3. The outlet end 15 of the rotary valve has a passage16 of a somewhat greater diameter than the inlet 12 for co-operatingwith the port 17 in the body portion 3 to lead away any dust and air inthe valve chamber.

Lubricator fittings 22 and 23 provide means for supplying lubricant tothe sleeves 8 and 9 and member 10, the lubricant also serving to sealthe relatively movable parts against leakage of air into the casing 3.

The member 10 may be rotated by lever 21 attached to the inlet end 11 ofthe member. When member 10 is rotated the ports 13 and 16 are alignedwith ports 14 and 1'7 respectively in one position or moved out ofalignment in another position. Thus simple rotation of member 10provides an air passage from outside the casing 3, through the latterand into conduits 18 and 19, or to close this passage completely.

It will be noted that the portions 4 and 5 extend inwardly some distancefrom the adjacent end walls of the casing 3 and fairly close to thebottom of the casing; also that the upper side Walls of the casingproject outwardly near the inlet end. By reason of these configurationsand the angle of repose of dust in the casing there are provided freespaces about the ports 14 and 17 and other spaces at 3' all of which arein communication with each other 'and constitute a gas passage from oneport to the other through casing 3.

The air or other gaseous fluid as it enters the inlet port 14 of thevalve passes upwardly and then horizontally across substantiallyopenpassages 3', formed by the contour of the side walls of the valve casingand the dust disposed therein, then downwardly and through the outlet orthe exhaust port 17 of the rotary valve member. By passing the gas dustand in contact with the surface of the dust, a small amount of dust willbe'picked up and .carried along, but will not be sufi'icient to clog theoutlet valve.-

Conduit 18 which connects with outlet 16 joins a main conduit 19 whichconnects through a suction creating device or ejector 20, with a conduit19a leading to a sump or other place of refuse disposal (shown in Fig.7)

In Figs. 5 and 6 I have shown a modified form of dust hopper dischargemeans embodying a substantially rectangular casing 24 including chambers29 and 30 adapted to be secured to the discharge opening in the bottomof a hopper l and having an outstanding lug or valve sleeve 25 formedintegrally with one horizontal wall and provided with a longitudinalbore 26 to receive valve 27 and a transverse bore 26 co-operable with asimilar bore 28 in valve 27. The aperture 28 is adapted to register withthe aperture 26 in the lug 25 to allow the suction of air or othergaseous fluid into the interior of the casing.

At the end of casing 24 remote from valve 27 an auxiliary chamber 30 islocated and in communication with conduit 32 leading through ejector 20to a place of refuse disposal (not shown). The chamber 30 is optionallyin communication with chamber 29 through an opening controlled by a fiapvalve or door 34. This door is connected to a shaft 35 counter-weightedas at 36 and provided with operating handles or levers 37. The shaft 35is also connected as by arm 38 and rod 39 to an arm 40 secured to valve27. Chains 41 may be connected to levers 37 to rotate shaft 35, open orclose door 34 and simultaneously rotate valve 27 to open or close theports 28 and 26.

The suction creating device or ejector indicated at 20 on Figs. 1 and 6is shown in some detail in Fig. 2. It comprises a fitting 42 having anaxial passage 43 of about the same size as conduits 19 and 32 and asurrounding chamber 44 communicating with conduit 48 and provided withnozzles 45 to discharge; fiuid under pressure converging past thedischarge end of passage 43 and into conduit 19. When fluid particularlyin the form of a liquid is discharged through the nozzles a strongsuction action is created and fine material, gases and air are therebydrawn through conduits 19 or 32 and connected conduits.

In operating the device of Figs. 1, 3 and 4, dust ash is permitted toaccumulate in casings 3 and hoppers 1 for a period of time. When thedust ash is to be removed, fluid is supplied under pressure to theconduit 48 and is eifective to create a reduced pressure area inconduits 19 and 18, that is, a zone of higher vacuum than exists in thehopper. Valve 10 is rotated to open ports 13 and 14, and 16 and 17, airor other gas is drawn through passage 12 and through casing 3 carryingwith it the fine ash disposed therein. When the air or gas and dustreach ejector 20 they are mixed with the fluid from conduit 48 andpropelled to the disposal point. This action is continuous until the ashis substantially all removed from hopper 1 and casing 3 and during theentire time no gas can escape into the chamber above the hopper becausethe suction created by the ejector is greater than that produced by theinduced draft fans in the furnace.

When all the dust has been removed from any casing 3 the valve 10 isrotated to close the ports 13 and 14, and 16 and '17. One or morecasings may be discharged at the same time.

The operation of the devices of Figs. 5 and 6 is substantially like thatjust described, except that valve 27 and flap door 34 are opened topermit ash discharge and closed when the ash is all removed. This deviceof Figs. 5 and 6 may be employed where there is little or no danger ofthe dust clogging the conduits.

In operating the systems of Figs. 1 or 6 several 4 auxiliary phases ofthe operation and apparatus are important. It is desirable that somemeans he provided for indicating the fact that the dust has all beenremoved from a hopper. It is also desirable that means should beprovided for preventing any back flow of dust laden liquid in conduitswhen the suction creating devices are shut off. If back flow occurs thenozales may become clogged. Furthermore, it is deale that provision bemade for using steam when the fluid supply as a suction producing mediumin the system, preferably in conjunction with other fluid since steammaybe employed to attenuate the air or gas in the system and thereby createsome of the vacuum or suction required.

In Fig. 7 these various considerations have been represented by suitableapparatus. In this figure, is diagrammatically shown a complete dusthandling system. The hoppers 1, casings 3 and conduits 18 and 19 of Fig.1 are similarly identified by reference characters, the conduit 19discharging into a sump 51.

An ejector. 20, adapted for use with fluid such as water, and anotherejector 52, adapted for use with a fluid such as steam are associatedwith the conduit 19. These ejectors may be similar in construction andeither may be operated alone or both together. The ejector 52 may bestarted first to attenuate the gas in the system andthe ejector 20 thenstarted to carry on the vacuum so created or increase it and therebyeffecting the transmission of gas through the system.

A vacuum gauge 53 communicating with the conduit 19 serves to indicatethe degree of vacuum in the conduit. Since the vacuum will decrease whenthe dust is cleared out of a given hopper because the air or gas canflow through the valves more freely, the gauge will indicate when thedust has been removed from the hopper. The gauge should be located onthe intake side of the first ejector nearest the hopper. As shown inFig. 7 it may be used when ejector 52 is not in use.

To prevent back flow of liquid and dust in conduit 19 I have provided ameans automatically operative to break the vacuum in the conduit to theejector 20 is shut oil. This device includes a bypass valve structure 59which operates simultaneously with the valve 60 to relieve any vacuumpressure in the main conduit 19. The valve 59 comprises a casing 61having one end thereof disposed in the conduit 19. A fluid pressure frompipe 62 is adapted to lead the main supply line 63 to a piston chamber64 having a piston 65 recipro-v cably mounted therein. The piston 65 hasstems 66 and 67 mounted on the opposing sides thereof. The end of thestem 66 is secured to a spring '70 which is in turn secured in the endwall of the piston chamber. The outer end of the stem 67 has a seatvalve 68 secured thereto. When the valve 68 is open communication iseifected between the interior of the discharge line 19 and theatmosphere through port 69 in the wall of the casing 61. Under normaloperation the suction creating device being in operation the valve isheld in seated position by fluid pressure acting against the upper faceof the piston 65. When the valve 60 is closed pressure is relieved inthe piston chamber and the valve 68 is unseated by the spring '70 to.relieve any pressure in the conduit 19.

The location of pressure gauge, ejector controls and suction breakersall at one place make the, apparatus susceptible to control from acommon station. If in addition the valves are equipped with operatingdevices, such as fluid pressure valves, they may be controlled from thecommon station and have the entire apparatus andits operation broughtunder the control of one person.

In cases where the gas when mixed with air will form an explosivemixture, the gas in the hopper or dust container may be used indischarging the dust. Apparatus for this purpose is shown in Fig. 8which embodies the apparatus of Fig. 1 with an added part. This addedconstruction embodies a conduit '76 having one end communicating withthe interior of the hopper 1 as at 77 and above the highest level ofdust therein, and the other end thereof cooperating with the inlet end11 of the rotary valve. When the valve is opened and the ejector createsa suction in casing 3, gas is drawn from hopper 1 into passage 12 andthe dust is removed as above described but without the formation of anydangerous gas mixture. It will be understood that similar additions maybe made to the apparatus of Fig. 6.

Although the foregoing description is necessarily of a detailedcharacter in order that the invention may be completely set forth, it isto be understood that the specific terminology is not intended to berestrictive or confining, and that various rearrangements of parts andmodifications of structural detail may be resorted to without departingfrom the scope of the invention as herein claimed.

I claim:

1. In apparatus for handling finely divided material. the combination ofa hopper having a dischargeopening, a valve housing secured to saidhopper and in communication with said opening, said housing having airinlet and outlet passages, means for simultaneously opening and closingsaid passages, and means for creating a suction in the said outletpassage.

2. In apparatus for discharging finely divided material, the combinationof a hopper having a discharge opening, a valve housing secured to saidhopper and communicating with said opening, said housing having an airinlet passage adapted to connect the interior of said housing to theatmosphere and an oppositely disposed outlet passage to connect theinterior of the housing with a conduit, means for simultaneously openingand closing said inlet and outlet passages, a conduit leading from saiddischarge opening, and means for creating a suction in said conduit.

3. The combination with the dust chamber of a fuel burning chamber, of acasing adapted to receive fine ash from said chamber, valve means in thecasing adapted to simultaneously open the interior of the casing to theatmosphere and to a conduit, and suction creating means in said conduitfor creating a partial vacuum in the conduit and casing and for drawinggas through the casing whereby the fine material therein will be carriedout through the conduit.

4. In apparatus of the class described, a hopper having a bottomdischarge opening, a valve housing below said discharge opening andadapted to receive material therefrom, valve mechanism in said housing,a conduit leading from said housing, means associated with said conduitfor creating a partial vacuum therein, said valve mechanism beingadapted when in one position to close off said valve housing from saidconduit and the atmosphere and when in another to es tablish connectionsbetween said valve housing, said conduit and the atmosphere.

5. In apparatus of the class described, a hopper having a dischargeopening, a valve housing adapted to receive material from said dischargeopening, said valve housing having oppositely disposed'gas inlet andoutlet openings, a conduit leading from the gas discharge opening ofsaid. 150

valve housing and adapted to carry material therefrom, said inletopening being adapted to provide a passage between said housing and theatmosphere, valve means in said valve housing, said valve meansincluding interconnected closure members adapted to open and close saidinlet and outlet openings simultaneously, and means for creating apartial vacuum in said conduit.

6. In apparatus of the class described, a hopper having a dischargeopening, a valve housing mounted on said hopper and adapted to receivematerial from said discharge opening, said housing having oppositelydisposed gas inlet and outlet openings, a conduit extending from saidgas outlet opening and adapted to carry away material dischargedtherethrough, a second conduit extending from said gas inlet opening tosaid hopper, valve means in said valve housing, said valve meansincluding interconnected closure members adapted to open and close saidinlet and outlet openings simultaneously, and means for creating asuction in the conduit which extends from the outlet opening of thevalve housmg.

7. In apparatus of the class described, a hopper having a dischargeopening, a valve housing adapted to receive material from said hopperdischarge opening, said valve housing having gas inlet and outletopenings, valve mechanism in said valve housing including interconnectedclosure members adapted to open and close said inlet and outlet openingssimultaneously, a conduit leading from said gas outlet opening, anejector associated with said conduit and adapted to create a suctiontherein, a conduit adapted to conduct fluid under pressure to saidejector, and fluid pressure actuated vacuum relief valve means,responsive to the fluid pressure within said conduit for conductingfluid to said ejector, said vacuum relief valve being adapted to connectthe conduit leading from the valve housing outlet to the atmosphere whensaid ejector is shut off.

8. In apparatus for handling finely divided material, the combination ofa hopper having a discharge opening, a valve housing secured to saidhopper and in communication with said hopper, said housing having'airinlet and outlet passages, means for positively and simultaneouslyopening and closing said passages and means for creating a suction insaid outlet passage.

9. The combination with combustion furnace, said ash hopper having adischarge opening, of a valve housing secured to said hopper and incommunication with said discharge opening, said housing having air inletand outlet passages, means for simultaneously opening and closing saidpassages and means for creating a suction in said outlet passage.

FRANK B. ALLEN.

